Nature documentaries always go on and on about how fast a cheetah can run. Cats in captivity have been clocked at 65 miles an hour, the highest speed recorded for any land animal.
And yet, scientists know very little about how the animal runs in the wild, especially when on the hunt.
"You can look at it and say, 'Oh that's fast,' " says Alan Wilson, a veterinarian at the Royal Veterinary College, London. "But you can't actually describe what route it follows, or how quickly it's gone, or the details of [the] forces it has to exert to do that."
Wilson and his colleagues were curious to know more, so they tracked a group of wild cheetahs in the Okavango Delta in Northern Botswana, using a sophisticated radio collar they had designed.
"It has a GPS that gives you a position and speed five times a second," Wilson says. "It has got accelerometers, and gyroscopes and electronic compasses in it." Together, these instruments collected detailed information about the animals' movements — in particular how fast they ran, and when and how they changed directions.
The animals reached top speeds of 45 to 58 miles per hour, Wilson says. But "on an average hunt they're only achieving half the maximum speed." In other words, running at top speed didn't seem all that necessary for hunting. What mattered more was how fast the cheetahs could accelerate.
"We saw remarkably high accelerations, four times higher ... than we see for Usain Bolt when he ran his world record," says Wilson.
The animals were similarly quick in slowing down and turning sharp corners, Wilson says. "They can accelerate, they can maneuver. They can duck and dive. And that's what they need to do to capture their prey."
Data from the collars clearly showed that agility trumps speed, he says, especially in bringing a hunt to a successful end.
"That sort of end phase when they're maneuvering, when they're turning sharply, when they're stopping and starting, is when the prey will escape or not escape," says Wilson. So it's the last stages of the hunt where the cheetah's maneuverability plays a key role.
"We've all seen footage of cheetah chasing prey," says Andrew Biewener, a biologist at Harvard University who studies locomotion in various animals. But this is the first study, he says, to provide hard data on exactly how wild cheetahs move.
What's more, the collars are helping scientists paint a more complete picture of how cheetahs behave in their natural environment, Beiwener says, and that information could be a key to the survival of this endangered species.
The detailed data, he says, offer "more of a window into what kinds of habitats need to be protected to allow these animals to survive as increasing pressures are put on their natural wildlife areas."